Well cementing apparatus



April 1952 R. c. BAKER EIAL WELL CEMENTING APPARATUS 3 Sheets-Sheet 1 Filed Oct. ll, 1945 1Peafien C. Eakez, 59:11am Kukyef INVENTORS ATTORNEY April 22, 1952 R. c. BAKER ETAL 2,593,520

WELL CEMENTING APPARATUS Filed 001;. 11, 1945 3 Sheets-Sheet 5 Eeafim CLEateer, Bernard K2142 494 IN VENTORS ATTORNEY Patented Apr. 22, 1952 WELL CEMENTING APPARATUS Reuben C. Baker, Coalinga, and Bernard Kriegel, Los Angeles, Calif., assignors to Baker Oil Tools, Inc., Vernon, Caliii, a corporation of California Application October 11, 1945, Serial No. 621,696

22 Claims.

1 This invention relates to apparatus particularly useful in the cementing of easing, liners and similar conduits in well bores.

It is an object of the present invention-to provide an improved hydraulically operatedapparatus for controlling passage of cement slurry or other fluent materials between the interior of a casing and its surrounding well bore.

A further object of the invention is to provide an apparatus having sleeve valve controlled ports, in which the sleeve valve can be shifted hydraulically to port opening position without the necessity for displacing the fluid column'ahead' of the sleeve valve.

Another object of the invention is to provide an apparatus having ports controlled by an internal sleeve valve capable of being held in closed position over the ports by an external -hydrostatic head or pressure of fluid, to prevent back flow of the fluid into a casing or similar conduit of which the apparatu forms a part.

Yet another object of the invention is to provide an apparatus forming part of a casing or similar tubular string, in which the apparatus has ports controlled by a sleeve valve moved hydraulically to port opening position, then automatically shifted to closed position, and held in such closed position by the action of fluid externally of the apparatus.

This invention has other objects that will become apparent from a consideration of the various forms of apparatus shown in the drawings accompanying and forming part of the present specification. These forms will now be described in detail to illustrate the general principals of. the invention, but it is to be understood that such detailed description is not to be taken in a limited sense, since the scope of the invention is best defined by the claims appended hereto.

Referring to the drawings:

Figure 1 is a longitudinal sectional view of a cementing apparatus embodying the invention;

Figure 2 is a view similar to Figure 1, with parts of the apparatus illustrated in another operative position;

Figure 3 is a longitudinal section, correspondingto Figure 1, of a modified form of the invention;

Figure 4 is a view similar to Figure 3, with parts of the apparatu shown in another operative position;

Figure 5 is a longitudinal section of still another form of the invention; and

Figure 6 is a view similar to Figure 5, with some of the parts in another operative position.

In the form of the invention shown in Figures 1 and 2, the apparatus consists of a casing shoe S whose steel tubular member ID has an upper threaded box' II for securing the shoe to the lower end of an adjacent casing section B. A plug I2 is threaded, or otherwise suitably secured, in the lower end of the tubular member ID and may have its lower portion 13 rounded to serve as a guide for the casing string while it is being lowered in a well bore. The plug has a central passage it, including a valve chamber l5, in which a buoyant back pressure and float ball I6 is contained for upward movement into engagement with a valve seat H, to permit the casing string to be floated through the fluid in the well bore. The extent of downward movement of the back pressure ball l6 from its seat is limited by its engagement with the fingers l8 of a ball stop device l9 threaded, or otherwise secured, in the lower end of the plug guide l2.

The tubular member It of the shoe is provided with one or more cementing and circulating ports or lateral outlets 26, which are adapted to be controlled by a sleeve valve 2| whose lower end is initially held across the ports 20 by one or more frangible pins or shear screws 22 extending into the tubular member and an external circular groove 23 formed in the sleeve valve. The lower end of the sleeve valve is slidable along the tubular member, in effect, constituting a relatively large annular piston 24 slidable along the relatively large companion cylinder 25 formed by the inner wall of the tubular member. The upper end of the sleeve valve is reduced in external diameter to provide a relatively small annular piston 26 projecting upwardly into a small cylinder 21 formed by a tubular plug, barrel or sleeve 28 threaded into the upper portion of the tubular member [0.

Suitable side seals 29, 30 are mounted on the exteriors of the small and large pistons 26, 24 to prevent leakage in both directions between them and their respective cylinders 21, 25. When the shear screws 22 are intact and in the position disclosed in Figure 1, the side seal 30 on the large piston is disposed below the cementing ports 21) and the seals 29 on the small piston are disposed above these ports at the lower end of the barrel 28, thus preventing fluid from passing from the interior of the apparatus, or casing string, around the sleeve valve 2 l, and out through the cementing ports 20. When in this position, a shoulder 3| between the large and small pistons is spaced below the lower end 32 of the barrel 28, to permit upward travel of the sleeve valve when required. A plurality of bleeder ports 33 extend through the tubular member adjacent the lower end 32 of the barrel to facilitate upward movement of the sleeve valve 2 I.

The apparatus is threaded on the end of the lower casing section B to form the lowermost part of the casing string. It is to be understood,

however, that the apparatus could function as a casing collar at an intermediate point in the string. The shear screws 22 hold the sleeve valve 2| disposed in closed position over the cementing ports 23. If a float ball I6 is provided in the guide, it engages its seat H and permits floating of the casing through the fluid in the well bore to the desired point. Circulation can then be established through the casing for as long as desired, the circulating fluid passing downwardly through the entire casing string, through the central passage [4 in the guide and plug l2, around the float ball 16, which is then resting on the ball stop fingers l8, and out of the lower end of the shoe, for upward passage around the casing string to the top of the well bore. When the cementing ports are to be opened a trip ball or valve 34 is pumped or allowed to gravitate through the fluid in the casing, until it engages a companion valve seat 35 at the upper end of the plug, closing its passage [4 and allowing fluid pressure to be built up in the casing string to the predetermined degree required to shear the screws 22 and elevate the sleeve valve 2i to its uppermost position, as determined by engagement of its shoulder 3| with the lower end 32 of the tubular plug 23. When such engagement occurs, the lower end of the sleeve valve 2| has been elevated above the cementing ports 20, which are now open to permit fluid passage between the interior of the casing string and its exterior.

The sleeve valve 2! moves in an upward direction because of the difference in the areas of the fluid pressure actuatable surfaces on the sleeve valve on which the fluid pressure is acting in both upward and downward directions. The annular fluid pressure actuatable area of the small piston 26 is denoted on the drawings by the letter A. Fluid pressure acts downwardly on the sleeve valve over this area and tends to move it in the same direction. The fluid pressure actuatable annular area of the large piston 24 acted upon by pressure internally of the apparatus is designated by the letter B. Fluid pressure interiorly of the apparatus acts upwardly on the sleeve valve over this area and tends to move it in an upward direction. Since the area B is greater than the area A, the resultant force acts in an upward direction over an area equivalent to B-A, and when the fluid pressure is increased sufficiently to exceed the equivalent shear value of the frangible screws 22, they are disrupted to release the sleeve valve 2| and permit its hydraulic elevation to port opening position, as disclosed in Figure 2.

After the ports are open, circulating fluid may be pumped down the casing string and out through the ports for as long a period as desired, after which the required amount of cement slurry is pumped down the casing string for ejection through the cementing ports 20 and upward passage through the well bore around the casing string. The trip or bridge ball 34 prevents downward movement of the cement slurry and circulating fluid through the central shoe passage [4. After the required amount of cement slurry has been ejected, the pressure can be maintained on the fluid in the casing to prevent back flow of the cement slurry into the shoe and casing string.

If desired, the aforementioned return flow of slurry can be prevented by providing a back pressure valve in the sleeve valve. As disclosed in Figures 1 and 2, such back pressure valve consists of a valve seat 36 clamped to the sleeve 2| by a suitable clamp nut 31. A back pressure ball 38, preferably buoyant in cement slurry, is located within the confines of the large piston 24, its downward movement being limited by a suitable ball stop in the form of a rod 39 secured to and extending across the sleeve valve. When fluid is being pumped down through the casing string, this back-pressure ball 38 rests on the rod stop 39 and against the wall of the large piston 24, leaving sufficient space around it for passage of the trip ball 34. That is, the trip ball 34 may pass through the casing string, the passage in the small piston 26 and valve seat 36, and then detour around the ball 38 and through the interior of the large piston 24, and between the ball stop rod 39 and guide plug I2, into engagement with its companion seat 35 at the upper end of the plug.

After the required amount of cement slurry has been ejected through the ports 20 in the shoe, the bleeding off of pressure in the casing will cause the slight return movement tendency of the cement slurry through the cementing ports back into the casing string to elevate the back pressure ball 38 into engagement with its seat 33 and preclude such return flow of the slurry deposited behind the casing.

The form. of apparatus disclosed in Figures 3 and 4 is similar in most respects to the apparatus just described, with the exception that return flow of the cement slurry into the shoe and casing string is prevented without the necessity for the back pressure ball valve mechanism. A valve closing helical spring 40 is inserted between the lower portion of the barrel 28 and a suitable socket 4! formed in the shoulder portion 3| of the sleeve valve. After the tripping ball 34 has engaged its companion seat 35 at the upper end of the plug [2 and pressure has been built up to disrupt the shear screws 22 and elevate the sleeve valve 2| to port opening position, the required amount of cement slurry may be ejected through the shoe ports 20 (see Figure 4). After such ejection, the holding of pressure on the easing string for a comparatively short interval creates an equalized pressure condition on both sides of the sleeve valve. That is, the same pressure acts in a downward direction over the sum of the area A and the annular area C between the inner wall of the tubular member I0 and inner wall of the small cylinder 21 as acts in an upward direction over the equal area B, allowing the helical spring 43, which has been further compressed by the upward movement of the sleeve valve 2|, to shift the sleeve valve to a downward port closing position, with its lower side seal 30 disposed below the cementing ports (as in Figure 3). The bleeding oil of pressure inside the casing now causes the greater hydrostatic head of cement slurry externally of the casing to act through the bleeder ports 33 in a downward direction over the area C at the shoulder portion 3| of the sleeve valve, holding the sleeve valve in such downward port closing position and preventing return flow of the cement slurry into the casing.

The form of invention disclosed in Figures 5 and 6 is similar in general operating features and characteristics to the other forms of the invention. The sleeve valve is so arranged as to move in a downward direction instead of an upward direction, but the same principle of having the internal fluid pressure act over diiferential areas to shift the sleeve valve is, nevertheless, utilized.

in Figures 5 and 6, the apparatus does not-disclose the use of a back pressure float valve l6, although this could be incorporated in the device,

if desired. The tubular member It] has a guide plug I2a' suitably secured in its lower end, and is also provided with a valve seat 35a for the tripping or bridging ball 3d. The upper portion of the tubular member Ill comprises the large cylinder 25a along whose wall the large upper piston 24 of the sleeve valve Zia is slidable. The lower, smaller piston 26a. of the sleeve valve is slidablewithin a smaller cylinder 21a formed in the lower plug [2a. The shear screws 22 hold the large piston 24a in port closing position over the side ports 20a in the tubular member ID, leakage between the large piston and tubular member being prevented by suitable side seals 30a disposed in grooves G2 in the piston on opposite sides of the ports 29a. Similarly, leakage between the smaller piston 25a and the wall of the small cylinder Hat is prevented by a suitable piston ring or side seal 29;: disposed in a lower piston groove 43.

The apparatus is attached to an adjacent casing section R and is lowered through the fluid in the casing string, with the shear screws 22 holding the large piston portion Z ta of the sleeve valve in port closing position. Fluid is circulated down through the apparatus and out through the shoe without passing through the ports 20a. When the ports are to be opened, the tripping ball 34 is lowered or pumped down through the fluid in the casing string until it engages its seat 35a in the plug of the shoe, closing the passage Ma through the latter and allowing pressure to be built up to a sufficient degree to shear the screws 22. The fluid pressure internally of the casing and apparatus acts in a downward direction over the large annular area B of the sleeve valve Zla, and in an upward direction over the smaller annular area A of the sleeve valve, producing a differential area of B-A on which the resultant fluid force is acting in a downward direction. When the pressure has been increased to the predetermined degree required to shear the screws, the sleeve valve 2 la is shifted downward- 13* until its upper end is below the cementing ports 2061, thus opening the latter (see Figure 6). Such downward shifting is facilitated by the provision of bleeder ports 33a below the cementing ports 20a adjacent the upper end of the plug I2a, allowing the fluid in the space between the tubular member If! and small piston 26a to escape to the exterior of the casing.

After the required amount of cement slurry has been pumped through the ports 20a, the pressure can be maintained internally of the casing until the cement has set and hardened. However, it is preferred to positively prevent return flow of cement slurry into the casing string. To effectuate this purpose, a helical spring 4% is disposed between the upper end of the plug l2a and the large piston 24a of the sleeve valve, which is compressed upon lowering of the sleeve valve 2m by the hydraulic action of the fluid under pressure in the casing. When all of the cement slurry has been ejected from the casing,

the pressure internally and externally of the easing string can be momentarily equalized, which equalizes the pressure acting on both sides of the sleeve valve. That is, the same pressure acts in a downward direction over the large area B as acts over the combined equal area A and C, allowing the compressed helical spring dila to shift the sleeve valve 2 la back to port closing position over the ports 20a, as determined by engagement of the sleeve valve with a suitable upper stop, which could be the lower pin end st of the adjacent casing section R (as in Figure 5) Thereafter, the internal pressure in the casing may be relieved and the hydrostatic pressure of the cement slurry passes through the bleeder ports 33!], for action onthe under side of the large piston in an upward direction, holding the sleeve valve in its uppermost closed position.

Substantially all internal parts of the shoe are made of readily drillable materials, such as magnesium or aluminum, to enable the bore of the shoe to be drilled out after the cement has hardened and leave an unrestricted passage therethrough.

It is apparent from the foregoing specific description that apparatus has been provided in which all of the circulating fluid can be pumped down through the central portion of the apparatus without passing through its side ports. Thereafter, upon opening of the ports, the fluid is prevented from passing down through the apparatus, but is restricted for passage in an outward direction through the lateral ports or outlet. It is unnecessary to move bodily any columns of fluid below the sleeve valve, since the tripping or bridging ball 34 comes to rest upon an immovable seat 35 or 35a, on the plug E2 or I211, and not upon the sleeve valve itself, as in prior art devices. After the required amount of cement slurry has been displaced through the casing ports, it is prevented from flowing back into the casing by the simple expedient of bleeding off of the pressure within the casing.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a sleeve valve within said means for controlling passage of fluid through said port, said sleeve valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, one of said areas being greater than the other to cause said sleeve valve to be moved hydraulically by the fluid within said tubular means to port opening position.

2. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a valve within said means for controlling passage of fluid through said port, said valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, one of said areas being greater than the other to cause said valve to be moved hydraulically to port opening position by the fluid Within said tubular means.

.3. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit sothat said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a valve within said means for controlling passage of fluid through said port, said valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously'by fluid within said tubular means, one of said areas being greater than the other, and means in said tubular means for impeding passage of fluid through said tubular means below said valve to enable fluid pressure within said tubular means to be increased for simultaneous action upon said areas to shift said valve to port opening position.

4. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part ofthe conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a longitudinally slidable valve within said means for controlling passage of fluid through said port, said valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be simultaneously subjected to the action of fluid within said tubular means, one of said areas being greater than the other to cause said valve to be moved longitudinally to port opening position by said fluid within said tubular means.

5. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a longitudinally slidable valve within said means for controlling passage of fluid through said port, said valve, having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be simultaneously subjected to the action of fluid within said tubular means, one of said areas being greater than the other, and means in said tubular means for impeding passage of fluid through said tubular means below said slidable valve to enable fluid pressure within said tubular means to be increased for simultaneous action upon said areas to shift said valve toport opening position.

6. Well apparatus, including tubular means having instrumentalities thereon for attaching said, means to a conduit so that said tubular means can form part of thepconduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a sleeve valve within said means initially closing said port, said sleeve valve having a first fluid pressure actuatable surface responsive to the pressure of fluid within said tubular means for urging said sleeve valve to port opening position, said sleeve valve also'having a second fluid pressure actuatable'surfaceof less area than said first-mentioned surface and responsive to the pressure of the same fluid within said tubular means as said first surface for urging said sleevevalve to port closing position, and

means in said tubular means for substantially preventing passage of fluid through said tubular means below said sleeve valve to enable fluid pressure within said tubular means to be increased for simultaneous action upon said surfaces to shift said sleeve valve to port opening position.

7. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a valve within said means for controlling passage of fluid through said port, frangible means for securing said valve to said tubular means in closed position with respect to said port, said valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, one of said areas being greater than the other to cause the hydraulic force of the fluid within said tubular means to disrupt said frangible means through action on said valve and shift said valve to port opening position.

8. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a longitudinally slidable valve within said means for controlling passage of fluid through said port, frangible means for securing said valve to said tubular means inclosed position with respect to said port, said valve having oppositely facing fluid pressure.

actuatable areas and a passage establishing com,- munication between said areas so that said areas can be simultaneously subjected to the action of the same fluid withinsaid tubular means, one of said areas being greater than the other, and means in said tubular means for impeding passage of fluid through said tubular means below said slidable valve to enable fluid pressure within said tubular means to be increased for simul taneous action upon said areas to disrupt said frangible means and shift said valve longitudinally to port opening position.

9. Well apparatus, including a tubular member adapted to form part of a conduit positioned within a well bore, said tubular member having a side port providing a fluid passage between the interior of said tubular member and the surrounding well bore, a tubular plug within said member having an inside diameter smaller than the inside diameter of said member, a sleeve valve within said tubular member and plug initially disposed over said port, said sleeve valve having large and small annular piston portions slidably engaging the inner walls of said tubular member and plug, respectively, in leakproof relaa side port providing a fluid passage between the interior of said tubular member and the surrounding well bore, a tubular plug within said member having an inside diameter smaller than the inside diameter of said member, a sleeve valve within said tubular member and plug initially disposed over said port, said sleeve valve having large and small annular piston portions slidably engaging the inner walls of said tubular member and plug, respectively, in leakproofrelation, and means movable into said tubular member and through said sleeve valve for impeding passage of fluid through said tubular member below said sleeve valve to enable fluid pressure within said tubular member to be increased and act simultaneously upon said piston portions to shift said sleeve valve to port opening position.

11. Well apparatus, including a ported tubular member having a, fluid passage and adapted to form part of a conduit positioned within a well bore, a tubular plug within said member having an inside diameter smaller than the inside diameter of said member, a sleeve valve within said tubular member and plug, frangible means for initially securing said sleeve valve in closed position over said port, said sleeve valve having large and small annular piston portions slidably engaging the inner walls of said tubular member and plug, respectively, in leakproof relation, and means adapted to be sent down through said conduit and through said sleeve valve into engagement with said member for restricting the passage through said tubular member below said sleeve valve whereupon fluid pressure within said tubular member may be increased for simultaneous action upon said piston portions to disrupt said frangible means and shift said sleeve valve to port opening position.

12. Well apparatus, including a tubular member adapted to form part of a conduit positioned within a well bore, said tubular member having a side port providing a fluid passage between the interior of said tubular member and the surrounding well bore, a tubular plug within said member having an inside diameter smaller than the inside diameter of said member, a sleeve valve within said tubular member and plug initially disposed over said port, said sleeve valve having large and small annular piston portions slidably engaging the inner walls of said tubular member and plug, respectively, in leakproof relation, means in said tubular member for impeding passage of fluid through said tubular member below said sleeve valve to enable fluid pressure within said tubular member to be increased and act simultaneously upon said piston portions to shift said sleeve valve to port opening position, said tubular member having a bleeder port establishing communication between the exterior of said tubular member and its interior around said sleeve valve.

13. Well apparatus, including tubular means having instrumentalities thereon for attaching said means tota conduit so that said tubular means can formpart of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a valve within said means for controlling passage of fluid through said port, said valve having oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid.,wlthin said tubular meansfone of said areas being greater than member to 10 cause said valve to be moved hydraulically by the fluid in said tubular means to port opening position, and spring means engaging said valve for moving it to port closing position.

14. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a longitudinally slidable valve within said means for controlling passage of fluid through said port, said valve having oppositely facing fluid pressure actuatable areas and a' passage establishing fluid communication between said areas so that said areas can be simultaneously subjected to the action of fluid within said tubular means, one of said areas being greater than the other, means in said tubular means for impeding passage of fluid through said tubular means below said slidable valve to enable fluid pressure within said tubular means to be increased for simultaneous action upon said areas to shift said valve to port opening position, and spring means engaging said valve for moving it to port closing position.

15. Well apparatus, including a tubular member adapted to form part of a conduit positioned within a well bore, said tubular member having a side port providing a fluid passage between the interior of said tubular member and the surrounding well bore, a tubular plug within said member having an inside diameter smaller than the inside diameter of said member, a sleeve valve within said tubular member and plug initially disposed over said port, said sleeve valve having large and small annular piston portions slidably engaging the inner walls of said tubular member and plug, respectively, in leakproof relation, means in said tubular member for impeding passage of fluid through said tubular member below said sleeve valve to enable fluid pressure within said tubular member to be increased and act simultaneously upon said piston portions to shift said sleeve valve to port opening position, and spring means engaging said tubular plug and sleeve valve for moving said valve to port closing position.

16. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a fside port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a sleeve valve within said means for controlling passage of fluid through said port, said sleeve valve having oppositely facing upper and lower fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can the'interior of-said tubular meansv and the surrounding-well bore,:a sleeve valve within said means for controlling the passage of fluid through said port, said sleeve valve having upper and lower oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, said lower area being greater than said upper area and means in said tubular means for enabling fluid pressure within said tubular means to act on said lower area to shift said valve upwardly to port opening position.

18. Well apparatus, including tubular means W having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned within a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a sleeve valve within said means for controlling passage of fluid.

through said port, said sleeve valve having upper and lower oppositely facing fluid pressure actuatable areas and 'a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, said lower area being greater than said upper area and means adapted to be sent down said conduit and through said sleeve valve into engagement with said tubular means for substantially closing the,

passage through said tubular means below said sleeve valve and permit fluid pressure within said tubular means to be increased and elevate said sleeve valve therewithin to port opening position.

19. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned within a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, said means having a valve seat rigidly secured to it below said port, a longitudinally movable sleeve valve within said tubu- ;-.4,5

lar means for controlling passage of fluid through said port, said sleeve valve having upper and lower oppositely facing fluid pressure actuatable areas and a passage establishing fluid communication between said areas so that said areas can be acted upon simultaneously by the same fluid within said tubular means, said lower area being greater than said upper area and means adapted to be sent down through said conduit into engagement with said valve seat to close the passage through said tubular means below said sleeve a valve and permit fluid pressure within said tubufluid pressure actuatable surface responsive to" the pressure of fluid within said tubular means for urging said sleeve valve to port opening position, said sleeve valve also having a second fluid I pressure actuatable surface of less area than said first mentioned surface and responsive tdthepressure of fluid within said tubular means for urging saidsleeve valve'to port closing position, andmeans in said tubular means for substantially preventing passage of fluid through said tubular means below said sleeve valve to enable fluid pressure within said tubular means to be increased for simultaneous action upon said surfaces to shiftsaid sleeve valve to port opening position.

21. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a sleeve valve within said means initially closing said port, said sleeve valve having a central passage therethrough and a flrst fluid pressure actuatable surface responsive to the pressure of fluid within said tubular means for urging said sleeve valve to port opening position, said sleeve valve also having a second fluid pressure actuatable surface of less area than said first mentioned surface and responsive to the pressure of fluid within said tubular means for urging said sleeve valve to port closing position, and means movable through said sleeve valve into engagement with said tubular means below said sleeve valve to impede passage of fluid through said tubular means and enable fluid pressure within said tubular means to be increased for simultaneous action upon said surfaces to shift said sleeve valve to port opening position.

22. Well apparatus, including tubular means having instrumentalities thereon for attaching said means to a conduit so that said tubular means can form part of the conduit when positioned in a well bore, said tubular means having a side port providing a fluid passage between the interior of said tubular means and the surrounding well bore, a longitudinally slidable valve within said means for controlling passage of fluid through said port, said valve having oppositely facing upper and lower fluid pressure actuatable areas and a passage establishing communication between said areas so that said areas are simultaneously subjected to the action of the same fluid within said tubular means, said lower area being greater than said upper area, and means in said tubular means below said valve for impeding passage of fluid through said tubular means to enable fluid pressure within said tubular means to be increased for simultaneous action upon said areas to shift said valve upwardly to port closing position.

REUBEN C. BAKER. BERNARD KRIEGEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 650,650 Niehoff May 29, 1900 694,811 Whiting Mar. 4, 1902 836,347 Tittelbach ,Nov. 20, 1906 1,725,539 Riley Aug. 20, 1929 2,005,813 Thorsen June 25, 1935 2,136,015 Nicks Nov. 8, 1938 2,212,087 Thornhill Aug. 20, 1940 2,235,318 Halliburton- Mar. 18,1941 7 7 2,380,022 .Burt July 10, 1945 1 2,393,457 Burnett r -Jan..:22,1946 

